PDF-417 is a two-dimensional barcode which can store up to about 1,800 printable ASCII characters or 1,100 binary characters per symbol. The symbol is rectangular; the shape of the symbol can be adjusted to some extent by setting the width and allowing the height to grow with the data. It is also possible to break large amounts of data into several PDF-417 symbols which are logically linked. There is no theoretical limit on the amount of data that can be stored in a group of PDF-417 symbols.
The capacity of PDF-417 can be helpful in applications where the data must travel with the labeled item, where a host database is not always available for quick look-up. PDF-417 is being used for hazardous materials labeling; storing technical specifications and calibration data on electronic instruments; encoding fingerprints and photographs on the backs of drivers' licenses.
The maximum data density is determined by the smallest elements which can be reliably printed and scanned. Using the smallest recommended element size of 0.0075 inch wide and 0.010 inch high, the maximum data density in the binary mode is 686 bytes per square inch (106.2 bytes per square centimeter). In the printable ASCII mode the density is 1,144 characters per square inch (177.2 characters per square centimeter).
PDF-417 symbols require a 2-D scanner or imager, or a standard CCD or laser scanner and special decoding software (a wand scanner will not work). PDF-417 symbols can be printed using most professional-grade thermal transfer label printers on the market as well as laser and inkjet printers.